Как задать css стили для определенного фрагмента кода?

                
if ( preg_match("#Content-Length: ([0-9]+)#i",$x,$size) ) return intval($size[1]); else return 0;

                
                if (preg_match("#Content-Length: ([0-9]+)#i",$x,$size)) {
                    return intval($size[1]);
                } else {
                    $x = @file_get_contents($this->from);
                    $x = strlen($x);
                    return $x;
                }

$body_class = "";

$body_class = "dle_theme_dark";

$body_class = "dle_theme_dark";

$body_class = "dle_theme_a";

$body_class = "dle_theme_b";

$body_class = "dle_theme_c";

$body_class = "dle_theme_d";

$body_class = "dle_theme_e";

$body_class = "dle_theme_f";

$body_class = "dle_theme_g";

$body_class = "dle_theme_h";

$body_class = "dle_theme_i";

$body_class = "dle_theme_dark";